Audio LINE-IN input application. AN_SIM900_Audio LINE-IN Input_V1.01

Transcription

1 Audio LINE-IN input application AN_SIM900_Audio LINE-IN Input_V1.01

2 Document Title: Audio LINE-IN input application Version: 1.01 Date: Status: Document Control ID: Release AN_SIM900_Audio LINE-IN Input_V1.01 General Notes SIMCom offers this information as a service to its customers, to support application and engineering efforts that use the products designed by SIMCom. The information provided is based upon requirements specifically provided to SIMCom by the customers. SIMCom has not undertaken any independent search for additional relevant information, including any information that may be in the customer s possession. Furthermore, system validation of this product designed by SIMCom within a larger electronic system remains the responsibility of the customer or the customer s system integrator. All specifications supplied herein are subject to change. Copyright This document contains proprietary technical information which is the property of SIMCom Limited., copying of this document and giving it to others and the using or communication of the contents thereof, are forbidden without express authority. Offenders are liable to the payment of damages. All rights reserved in the event of grant of a patent or the registration of a utility model or design. All specification supplied herein are subject to change without notice at any time. Copyright Shanghai SIMCom Wireless Solutions Ltd AN_SIM900_Audio LINE-IN Input_V1.01 2

3 Contents Contents...3 Version history Introduction Scope of the document Recommended application circuit Audio input 1 single-ended LINE-IN input configuration Audio input 1 difference LINE-IN input configuration Audio input 2 single-ended line input configuration Recommended external components...8 AN_SIM900_Audio LINE-IN Input_V1.01 3

4 Figure Index FIGURE 1: MIC1 LINE-IN INPUT SINGLE-ENDED CONNECTION...6 FIGURE 2: MIC1 LINE-IN INPUT DIFFERENCE CONNECTION...7 FIGURE 3: MIC2 LINE-IN INPUT SINGLE-ENDED CONNECTION...7 Table Index TABLE 1: RECOMMENDED EXTERNAL COMPONENTS...8 AN_SIM900_Audio LINE-IN Input_V1.01 4

5 Version history Date Version Description of change Author Origin LiGang AN_SIM900_Audio LINE-IN Input_V1.01 5

6 1 Introduction This document describes how to set up the audio channel as LINE-IN input. The MIC2 input is only for the modules that have two analog audio input channels. For more details, please refer to related hardware design document. 2 Scope of the document This document is intended for the following versions of the SIMCom modules SIM900/ SIM900A SIM900B/SIM900D 3 Recommended application circuit 3.1 Audio input 1 single-ended LINE-IN input configuration VMIC Module 1uF C1 MIC1P RL 2.2k Audio amplifer MIC1N 2.2k Figure 1: MIC1 LINE-IN input single-ended connection AN_SIM900_Audio LINE-IN Input_V1.01 6

7 3.2 Audio input 1 difference LINE-IN input configuration VMIC Module 1uF C1 1uF MIC1P RL 2.2K Audio amplifer C2 MIC1N 2.2K Figure 2: MIC1 LINE-IN input difference connection 3.3 Audio input 2 single-ended line input configuration 1uF C1 VMIC 2.2K 2.2K MIC2P RL Module Audio amplifer MIC2N 0R Figure 3: MIC2 LINE-IN input single-ended connection RL is used to adjust the bias voltage level. C1 and C2 are used for AC coupling capacitor. It is recommended to use MIC1 for line input application. If MIC2 is selected for LINE-IN input, the detection of audio accessories function will be disabled. AN_SIM900_Audio LINE-IN Input_V1.01 7

8 3.4 Recommended external components The following table shows some examples for external components selection. Table 1: Recommended external components Configuration Bias voltage RL C LINE-IN input range(pk-pk) MIC1 LINE-IN input 1.5V 1K 1uF <500mV single-end configuration MIC1 LINE-IN input 1.5V 1K 1uF <100mV difference configuration MIC2 LINE-IN input 1.2V 2.2K 1uF <100mV single-end configuration AN_SIM900_Audio LINE-IN Input_V1.01 8

9 Contact us: Shanghai SIMCom Wireless Solutions Ltd. Add: Building A,SIM Technology Building,No.633,Jinzhong Road,Changning District, Shanghai,P. R. China Tel: Fax: URL: AN_SIM900_Audio LINE-IN Input_V1.01 9